UPDATE 1-NASA's science rover Curiosity zaps first Martian rock

LOS ANGELES, Aug 19 (Reuters) - The Mars rover Curiosityzapped its first rock on Sunday with a high-powered laser gundesigned to analyze Martian mineral content, and scientistsdeclared their target practice a success.

The robotic science lab aimed its laser beam at thefist-sized stone nearby and shot the rock with 30 pulses over a10-second period, NASA said in a statement issued from missioncontrol at the Jet Propulsion Laboratory near Los Angeles.

Each pulse delivers more than 1 million watts of energy forabout five one-billionths of a second, vaporizing apinhead-sized bit of the rock to create a tiny spark, which isanalyzed by a small telescope mounted on the instrument.

The ionized glow, which can be observed and recorded from upto 25 feet (7 meters) away, is then split into its componentwavelengths by three spectrometers that give scientistsinformation about the chemical makeup of the target rock.

The combined system, called the Chemistry-and-Camerainstrument, or ChemCam, is capable of discerning more than 6,000different wavelengths in the ultraviolet, infrared and visiblelight spectrum and is designed to take about 14,000 measurementsthroughout Curiosity's Mars mission.

The purpose of Sunday's initial use of the laser, conductedat roughly 3 a.m. Pacific time (1100 GMT), was as "targetpractice" for the instrument. But scientists will examine thedata they receive to determine composition of the rock, whichthey dubbed "Coronation," NASA said.

"We got a great spectrum of Coronation - lots of signal,"said ChemCam principal investigator Roger Wiens of the LosAlamos National Laboratory in New Mexico, where the instrumentwas developed. "After eight years of building the instrument,it's payoff time."

Curiosity, a one-ton, six-wheeled vehicle the size of acompact car, landed inside a vast, ancient impact crater nearMars' equator on Aug. 6 after an eight-month, 354-million-milevoyage through space. Its two-year mission is aimed atdetermining whether or not the planet most like Earth could have hosted microbial life.

The rover's primary target is Mount Sharp, a towering moundof layered rock rising from the floor of Gale Crater. Butmission controllers are gradually checking out Curiosity'ssophisticated array of instruments before sending it on itsfirst road trip across the Martian landscape.

The $2.5 billion Curiosity project marks NASA's firstastrobiology mission since the Viking probes to Mars during the1970s and the most advanced robotic science lab sent to anotherworld.

The technique employed by ChemCam has been used to examinethe composition of materials in other extreme environments, suchas inside nuclear reactors and on the sea floor.

The technology also has experimental applications inenvironmental monitoring and cancer detection. But Sunday'sexercise, conducted during Curiosity's 13th full day on Mars,was the first use in interplanetary exploration, NASA said.

Before Curiosity embarks on its 4.3-mile (7-km) trek to thefoot of Mount Sharp, a journey that could take six months,mission controllers plan to send it out on a shorter jaunt to aspot 1,600 feet (500 meters) from its landing site.